Tomoe really carry MC behind the scene as strategist. She became more creative because of her obsession with Japan by learning it from his memories. Everyone been concerned and bothered when she hide some secret from MC, but I think that's the wise choice based on how MC act so far. He couldn't digest "too much information" pouring into him at once (Tomoe and Mio already talk about this before and MC order them to do so, forgot what chapter it is), so the solution is to let it go as natural as it can be for him, one by one. Whether he found it by his own effort or by miracle or he's sharp enough to notice it beforehand and confront it. I can imagine, if MC learns about Rembrant's past at this point, I 100% sure that he can't think straight, he will look at Rembrant with his psychopath eyes, and not trusting him anymore.
He need to be mature enough and decisive with his decision. And now is not the time yet, he need to learn and see the world, widening his horizon, learn the common sense, and basic knowledge. I hope I can see his growth as character and be mature. I hope.
